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Posts Tagged ‘astrophysics

“I was a peripheral visionary. I could see the future, but only way off to the side.”*…

Artist’s concept of the Earth 5–7.5 billion years from now, when the Sun has become a red giant. (source)

As Niels Bohr said, “prediciton is hard, especially about the future.” Still, we can try…

While the future cannot be predicted with certainty, present understanding in various scientific fields allows for the prediction of some far-future events, if only in the broadest outline. These fields include astrophysics, which studies how planets and stars form, interact, and die; particle physics, which has revealed how matter behaves at the smallest scales; evolutionary biology, which studies how life evolves over time; plate tectonics, which shows how continents shift over millennia; and sociology, which examines how human societies and cultures evolve.

The far future begins after the current millennium comes to an end, starting with the 4th millennium in 3001 CE, and continues until the furthest reaches of future time. These timelines include alternative future events that address unresolved scientific questions, such as whether humans will become extinct, whether the Earth survives when the Sun expands to become a red giant and whether proton decay will be the eventual end of all matter in the Universe…

A new pole star, the end of Niagara Falls, the wearing away of the Canadian Rockies– and these are just highlights from the first 50-60 million years. Read on for an extraordinary outline of what current science suggests is in store over the long haul: “Timeline of the far future,” a remarkable Wikipedia page.

Related pages: List of future astronomical events, Far future in fiction, and Far future in religion.

* Steven Wright


As we take the long view, we might send grateful birthday greetings to the man who “wrote the book” on perspective (a capacity analogically handy in the endeavor featured above), Leon Battista Alberti; he was born on this date in 1404.  The archetypical Renaissance humanist polymath, Alberti was an author, artist, architect, poet, priest, linguist, philosopher, cartographer, and cryptographer.  He collaborated with Toscanelli on the maps used by Columbus on his first voyage, and he published the the first book on cryptography that contained a frequency table.

But he is surely best remembered as the author of the first general treatise– De Pictura (1434)– on the the laws of perspective, which built on and extended Brunelleschi’s work to describe the approach and technique that established the science of projective geometry… and fueled the progress of painting, sculpture, and architecture from the Greek- and Arabic-influenced formalism of the High Middle Ages to the more naturalistic (and Latinate) styles of Renaissance.

Figure from the 1804 edition of Della pittura showing the vanishing pointsource)


“I have not yet lost a feeling of wonder, and of delight, that the delicate motion should reside in all the things around us”*…

The proton, the positively charged particle at the heart of the atom, is an object of unspeakable complexity, one that changes its appearance depending on how it is probed…

“This is the most complicated thing that you could possibly imagine,” said Mike Williams, a physicist at the Massachusetts Institute of Technology. “In fact, you can’t even imagine how complicated it is.”

The proton is a quantum mechanical object that exists as a haze of probabilities until an experiment forces it to take a concrete form. And its forms differ drastically depending on how researchers set up their experiment. Connecting the particle’s many faces has been the work of generations. “We’re kind of just starting to understand this system in a complete way,” said Richard Milner, a nuclear physicist at MIT.

As the pursuit continues, the proton’s secrets keep tumbling out. Most recently, a monumental data analysis published in August found that the proton contains traces of particles called charm quarks that are heavier than the proton itself.

The proton “has been humbling to humans,” Williams said. “Every time you think you kind of have a handle on it, it throws you some curveballs.”

Recently, Milner, together with Rolf Ent at Jefferson Lab, MIT filmmakers Chris Boebel and Joe McMaster, and animator James LaPlante, set out to transform a set of arcane plots that compile the results of hundreds of experiments into a series of animations of the shape-shifting proton…

Charlie Wood (and Merrill Sherman) have incorporated that work into an attempt to unveil the particle’s secrets: “Inside the Proton, the ‘Most Complicated Thing You Could Possibly Imagine’,” from @walkingthedot in @QuantaMagazine.

* Edmund Burke


As we ponder presumptive paradoxes, we might send insightful birthday greetings to David Schramm; he was born on this date in 1945. A theoretical astrophysicist, he established the field of particle astrophysics, a branch of particle physics that studies elementary particles of astronomical origin and their relation to astrophysics and cosmology. He was particularly well known for the study of Big Bang nucleosynthesis and its use as a probe of dark matter and of neutrinos. And he made important contributions to the study of cosmic rays, supernova explosions, heavy-element nucleosynthesis, and nuclear astrophysics generally.


Written by (Roughly) Daily

October 25, 2022 at 1:00 am

“‘Space-time’ – that hideous hybrid whose very hyphen looks phoney”*…

Space-time curvature [source: ESA]

Space and time seem about as basic as anything could be, even after Einstein’s theory of General Relativity threw (in) a curve. But as Steven Strogatz discusses with Sean Carroll, the reconciliation of Einstein’s work with quantum theory is seeming to suggest that space and time might actually be emergent properties of quantum reality, not fundamental parts of it…

… we’re going to be discussing the mysteries of space and time, and gravity, too. What’s so mysterious about them?

Well, it turns out they get really weird when we look at them at their deepest levels, at a super subatomic scale, where the quantum nature of gravity starts to kick in and become crucial. Of course, none of us have any direct experience with space and time and gravity at this unbelievably small scale. Up here, at the scale of everyday life, space and time seem perfectly smooth and continuous. And gravity is very well described by Isaac Newton’s classic theory, a theory that’s been around for over 300 years now.

But then, about 100 years ago, things started to get strange. Albert Einstein taught us that space and time could warp and bend like a piece of fabric. This warping of the space-time continuum is what we experience as gravity. But Einstein’s theory is mainly concerned with the largest scales of nature, the scale of stars, galaxies and the whole universe. It doesn’t really have much to say about space and time at the very smallest scales.

And that’s where the trouble really starts. Down there, nature is governed by quantum mechanics. This amazingly powerful theory has been shown to account for all the forces of nature, except gravity. When physicists try to apply quantum theory to gravity, they find that space and time become almost unrecognizable. They seem to start fluctuating wildly. It’s almost like space and time fall apart. Their smoothness breaks down completely, and that’s totally incompatible with the picture in Einstein’s theory.

s physicists try to make sense of all of this, some of them are coming to the conclusion that space and time may not be as fundamental as we always imagined. They’re starting to seem more like byproducts of something even deeper, something unfamiliar and quantum mechanical. But what could that something be?….

Find out at: “Where Do Space, Time and Gravity Come From?, ” from @stevenstrogatz and @seanmcarroll in @QuantaMagazine.

* Vladimir Nabokov


As we fumble with the fundamental, we might send far-sighted birthday greetings to Jocelyn Bell Burnell; she was born on this date in 1943. An astrophysicist, she discovered the first pulsar, while working as a post-doc, in 1957. She then discovered the next three detected pulsars.

The discovery eventually earned the Nobel Prize in Physics in 1974; however, she was not one of the prize’s recipients. The paper announcing the discovery of pulsars had five authors. Bell’s thesis supervisor Antony Hewish was listed first, Bell second. Hewish was awarded the Nobel Prize, along with the astronomer Martin Ryle.

A pulsar— or pulsating radio star– a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation. The precise periods of pulsars make them very useful tools. Observations of a pulsar in a binary neutron star system were used to  confirm (indirectly) the existence of gravitational radiation. The first extrasolar planets were discovered around a pulsar, PSR B1257+12.  And certain types of pulsars rival atomic clocks in their accuracy in keeping time.

Schematic rendering of a pulsar


Jocelyn Bell Burnell


Written by (Roughly) Daily

July 15, 2022 at 1:00 am

“I’m sure the universe is full of intelligent life. It’s just been too intelligent to come here.”*…

Email migration should now be complete; email subscribers should now be getting (Roughly) Daily via Mailchimp, and should not be getting a duplicate from Feedburner. If you are getting a dupe, please let me know (roughlydaily@gmail.com). Note that this new service may be landing in your Gmail “Promotions” folder; you can move it to your main folder. With apologies for the turbulence over the last few days, and thanks for your continued reading, on to today’s post…

A new computer simulation shows that a technologically advanced civilization, even when using slow ships, can still colonize an entire galaxy in a modest amount of time. The finding presents a possible model for interstellar migration and a sharpened sense of where we might find alien intelligence.

Space, we are told time and time again, is huge, and that’s why we have yet to see signs of extraterrestrial intelligence. For sure, the distances between stars are vast, but it’s important to remember that the universe is also very, very old. In fact, I’d go so far as to say that, in terms of extremes, the Milky Way galaxy is more ancient than it is huge, if that makes sense. It’s for this reason that I tend to dismiss distances as a significant variable when discussing the Fermi Paradox—the observation that we have yet to see any evidence for the existence of alien intelligence, even though we probably should have.

New research published in The American Astronomical Society is bolstering my conviction. The new paper, co-authored by Jason Wright, an astronomer and astrophysicist at Penn State, and Caleb Scharf, an astrobiologist at Columbia University, shows that even the most conservative estimates of civilizational expansion can still result in a galactic empire.

A simulation produced by the team shows the process at work, as a lone technological civilization, living in a hypothetical Milky Way-like galaxy, begins the process of galactic expansion… Things start off slow in the simulation, but the civilization’s rate of spread really picks up once the power of exponential growth kicks in. But that’s only part of the story; the expansion rate is heavily influenced by the increased density of stars near the galactic center and a patient policy, in which the settlers wait for the stars to come to them, a result of the galaxy spinning on its axis.

The whole process, in which the entire inner galaxy is settled, takes one billion years. That sounds like a long time, but it’s only somewhere between 7% and 9% the total age of the Milky Way galaxy.

As noted, the new model is constrained by some very conservative rules. Migration ships are launched once every 10,000 years, and no civilization can last longer than 100 million years. Ships can travel no farther than 10 light-years and at speeds no faster than 6.2 miles per second (10 kilometers per second), which is comparable to human probes like the Voyager and New Horizons spacecraft. 

“This means we’re not talking about a rapidly or aggressively expanding species, and there’s no warp drive or anything,” said Wright. “There’s just ships that do things we could actually manage to do with something like technology we can design today… Even under these conditions, the entire inner part of the simulated galaxy became settled in a billion years. But as Wright reminded me, our “galaxy is over 10 billion years old, so it could have happened many times over, even with those parameters.”…

A new simulation published by the American Astronomical Society suggests that aliens wouldn’t need warp drives to take over an entire galaxy in (relatively) short order, as George Dvorsky (@dvorsky) explains.

[Image above: Andromeda Galaxy, source]

* Arthur C. Clarke


As we spread out, we might spare a thought for Jacobus Cornelius Kapteyn; he died on this date in 1922. An astronomer, he used photography and statistical methods to determine the motions and spatial distribution of stars (especially with the Milky Way), the first major step after the works of William and John Herschel. He introduced absolute magnitude and color indexing as standard concepts in cataloguing stars.

Kapteyn was also among the first to suggest the existence of dark matter (which he deduced from examining stellar velocities).


“Oh, there you are Peter”*…


The missing links between galaxies have finally been found. This is the first detection of the roughly half of the normal matter in our universe – protons, neutrons and electrons – unaccounted for by previous observations of stars, galaxies and other bright objects in space.

You have probably heard about the hunt for dark matter, a mysterious substance thought to permeate the universe, the effects of which we can see through its gravitational pull. But our models of the universe also say there should be about twice as much ordinary matter out there, compared with what we have observed so far.

Two separate teams found the missing matter – made of particles called baryons rather than dark matter – linking galaxies together through filaments of hot, diffuse gas

Get galactic at: “Half the universe’s missing matter has just been finally found.”

* meme


As we heed E.M. Forster, we might recall that it was on this date in 1843 that Sir William Rowan Hamilton conceived the theory of quaternions.  A physicist, astronomer, and mathematician who made important contributions to classical mechanics, optics, and algebra, he had been working since the late 1830s on the basic principles of algebra, resulting in a theory of conjugate functions, or algebraic couples, in which complex numbers are expressed as ordered pairs of real numbers.  But he hadn’t succeeded in developing a theory of triplets that could be applied to three-dimensional geometric problems.  Walking with his wife along the Royal Canal in Dublin, Hamilton realized that the theory should involve quadruplets, not triplets– at which point he stopped to carve carve the underlying equations in a nearby bridge lest he forget them.



Written by (Roughly) Daily

October 16, 2017 at 1:01 am

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